# Why does the condensation cone disappears when the airplane starts flying supersonic

In this answer How are condensation cones created by supersonic airplanes? it is said that the condensation cones appear only when the airplane flies at speeds below Mach 1. I am wandering why does it disappear above Mach 1, and does the condensation cone appear when flying exactly at Mach 1?

• Exactly Mach 1 isn’t really a thing, as the airflow will accelerate to some degree as it passes over each aerodynamic surface.
– Frog
Sep 10, 2022 at 9:06